December 2. 2012 - The worst of the third storm to hit Northern California in less than a week passed over much of the region Sunday, leaving at least eight rivers at flood-watch stage.

Flood concerns, including for the Napa and Russian rivers north of San Francisco, will likely continue all week, said Brad Alexander, of the California Emergency Management Agency.

"We're through the tough part of the day," he said by midmorning Sunday.

The region was soaked this week when a series of storms dumped about 20 inches of rain -- 3 to 6 inches in the past 24 hours, said Todd Morris, meteorologist for the National Weather Service's western region.

The latest storm was the most severe of three consecutive storms that have drenched much of Northern California and Nevada since Tuesday. Parts of the region got more rain and snow in the last week than the average for the entire month of November.

Christmas parades and tree-lighting ceremonies in Sparks, Nev., and Truckee, Calif., were canceled because of the weather. Along the Northern California Coast, swells up to 14 to 16 feet were expected and a high surf advisory was issued.

"We'll have a break Monday, but we're going to see a fourth storm that's going to approach the West Coast," Morris said. "Fortunately for everybody in the West, this fourth storm appears to be weaker."

Sandbagging was going on in numerous cities, including Sacramento and Napa. So far, flooding has been on a small scale. "One house here, one there," Alexander said.

Jim Brandt, owner of the Napa General Store, surveyed the Napa River flowing 10 yards away from his window Sunday. The fast-moving water carried a lot of extra debris, but a massive flood wall protects the downtown in the city at the heart of wine country. The wall was under construction during a flood in Napa in 2005.

"We expect to stay dry," Brandt said. Minor flooding is more likely in more low-lying agricultural areas north of the city, he said.

Northern California and Nevada had more than rain to contend with. Winds were so strong that the Sierra at Tahoe, a Lake Tahoe ski resort, had to close Sunday. It's expected to reopen Monday.

Wind gusts of more than 60 mph hit the San Francisco Bay area and more than 70 mph in Reno. In higher elevations near Mammoth Ski Resort, winds exceeded 100 mph.

Officials were keeping an eye on hillsides burnt out in previous wildfires that are prone to mudslides in heavy rain.